More than 10,000 people are protesting in the Hungarian capital, demanding the ouster of the head of the tax authority and greater accountability from Prime Minister Viktor Orban's government.

The demonstration outside Parliament Monday was spurred by anger over Orban's refusal to dismiss Ildiko Vida, who has been issued with an entry ban by the United States because of alleged ties to corruption.

The event, dubbed "Public Outrage Day," was the fourth large anti-government rally held in Budapest in the past month. Smaller rallies were also held in 20 other Hungarian cities and in European capitals like London, Berlin and Stockholm.

Protest organizer Balazs Nemes blamed Hungary's whole political class for the country's problems, saying that "we are not here to bury a government but to bury a system."